braun



1953 A. F. BRAUN COMPOUND CARBURETION SYSTEM 2 Sheets-Sheet 1 Filed July 28, 1949 zadz zxziliii A. F. BRAUN COMPOUND CARBURETION SYSTEM Aug. 4, 1953 2 Sheets-Sheet 2 Filed July 28, 1949 Patented Aug. 4, 1953 UNITED E S- OFF ICEZ OMPOUN1T CARBURETION. SYSTEM corporation. o.Delaware Acpplication JiilY'ZS, 1949, SrialNo: 107L277 8 Claims;

invention; relates to compounoii carburetion systems for internal combustion engines, 1.v e carburetion systemsawhi'clm include: a pin ralityoi? carburetors whioi-rz communicate the; same: cylinder or: cyiindersrot the: engine and are so controlled that'whem tliezengine is operatmg at lower: speeds combustible mixture issupplied; to: the? cylinder? or: cylinders: by only one of the: carburetors anch when; the: engineiis operating at. higher speeds cozmhustiblez mixture issuppIie'd totthe cylinder: onzcylindens: bvapiurafity of the carburetor-5..

invention resides in: improvements in the compound carbonation system disclosed in my Unitedi States; Patent N022 2,434,192; dated J anu-- any 62,, tsfi by which therseoondamv: carburetor or: carburetors; are brought: into operation: with the minimum departure from. the: desired rate 015; acceierati'on: the; spseda oi; the: engine, which minimize the; discrepancies between the: volumes of? combustible: mixture: supplied, to. the several cylinders: of a muiti-cyiinden' enginsganoll: which minimize the height oh and render the: oarhuret ing; apparatus more compact Eor a. betterunderstanding'. oftheo objects andnatureofi thisiinvention, neference' is mad'e' to the. following. spscifioatiom omit. the: accompanying dnawing whereinz embodiments; of invention are: described: and illustrated;

In the; accompanying drawing;

Figure: I; is; at fragmentary side elevationofa: muitia-cylindert' internala combustion engine'- equipped with: carhuretihg. apparatus which nm' invention; is; embodied;

Eigures 21 is: an enlarged side elevation; with pamtstxbroliem awawand in section; of the secomiamr carburetor of- 'the carbureti'n'gapparathsshown innFiglme Figure: 3's is: a. sideel'evationg with partsbroken away and in section; of another embodimentof" myinventi'om Figures Land 5 are side elevations, with parts" bnolterraway and'insect'iong of a third-em-loodiment' ofl-myinvent'ion:

In" tho drawing; thereference character H1" indicates a multi cyiinder' internal combustion en'- ginei an intake manifol'zi' H which communicates' with a plurality of the cylindersof" theieng-inei @m the intake I manifold-3 forward of its midpoint, there-i's disposed a; primary carburetonliianditoi-the'rear ofits midpoint; a secondarszzcarbureton I 3;. The. primary carburetor may 1381301 511118? conventional type with: a mixture pas sage M4 there- 1 is disposed a Butterfly timottlez valve Its-mounted on a shot? F6 to: which (Cl. 123F121);

root: on a shaft 20- ano to there: is: alsm connected-a link- 2 F through which the lever I-S may be rocked by: the accelerator peoiat oft. the=- vehicle; To an: arm 22 on thel'even I 93 theredsi connected a spring 23 which biases the throttlevalve ii to its closed position;

The secondary carburetor I 3 includes a; mix:- ture passage 24 in which'there is: disposed aibutterflythrottle val ve' 2-5 which is mounted on at shaft" 2 6 On the: shaft 215: there is m'ounteoi so thatmay' rock an arm: 2T; To. the shatt: 28? there isfi'xed a dbub1e-armed1ever28 with-2a 29 011- one of its armsin the path of thearm when the latterismoved' the ditectiomtmolbse: the throttle valve The arm 21! is: connected. by'a link 311 to" a lever 3 l'whicl nis mountedtsw that i't' may rock on the shaft 211* in. the path of the lever I9 when the latter is: rocked to? opem the throttle valvet I 5. The lever. 31 isibiase'dshy a spring?! the: direction tamovevthe: arm 2-7: on: the shaft or the-throttle valve 25 ofi'the seconds ary' carburetor in the. direction; to close: the throt-v tIe' valve.

on: the secondary carburetor. li3zthenaissmountsed a pressure responsivei devibet which consistsfiot' an enclosure 3135 with. a flexibltr Wall? 3:4? which is' connected, by a. limit 35 to the arm: of the: lever? 28*whi'ch: doesmot carrythepin' 29:and issbiased: by a spring 38 in the: directionz to: close: the throttle valve; The: interior of the: enclosure: 33 is: connected: to? themixturepassage: of' the; 5835- ondary carburetor on the: engine: side? of thethrottle valve byr'a duct: which includes a tube:- 31 and a bore-"wtwith'za valve! housing. 39s interposed between them. In the valve? housing 3.9;. there is: disp'osedl a? piston valve 411: which; is: biased by at spring: M {3022}: position in whichv the tube 37 communicates-r with the: b'0116333"thf011gh? the valve"v housing 39 but: is movable by: suction-4 in the manifold lilxt'o atpnsitionin which it: terrupts comnmnication: betweem ther bore; and the tube;

'I'he lever I 9, oi' c'ourse; dbessnot' some intoflconztact with the lever 31 until thetthrottle valve: ti of'the primary carburetor has: been openedi. to a; pre-seleot'ed extenii. 6; g., about: one half: Com sequenti y; until the-thrott1e=-va1ve: of the:

1: carburetor has: been opened to. this: the throttle valve 25" oi the: secondary: carburetor is held closed by the springffll However; after the throttle; valve? of: the m1- ma'ry carburetor has: heem open'efl; to the: pro-- to selected extent, further: rrrovemerit 01% the a'ccelerator pedal in the direction to open the throttle valve of the primary carburetor will bring the lever is into contact with the lever 3! and, thereafter, move the latter with the former. This movement of the lever 3: will, through the link 30, move the arm 2? on the shaft of the throttle valve of the secondary carburetor out of contact with the pin 29 on the double-armed lever 28. The piston valve 40 is moved by the suction in the intake manifold M to a position in which it interrupts communication between the bore 38 and the tube 3'? only when the suction attains the high values it attains when the throttle valves are closed or nearly closed and serves to eliminate the tendency which the suction acting through the diaphragm 3d would otherwise have to open the throttle valve of the secondary carburetor under this condition. Consequently, when the throttle valve of the primary carburetor has been opened sufficiently to move the arm 2'! out of contact with the pin 29 the suction in the intake manifold will be applied to the diaphragm 34 and if the suction is sufficiently high will open the throttle valve of the secondary carburetor to the limit permitted by the arm 21. Therefore, after the throttle valve of the primary carburetor has been opened sufficiently to move the arm 21 out of contact with the pin 29 the position of the throttle valve of the secondary carburetor will depend upon the value of the suction in the intake manifold as well as upon the position of the throttle valve of the primary carburetor as is desirable in the interest of satisfactory operation of the engine under different loads. The movement of the arm 2'! is so correlated with the movement of the throttle valve of the primary carburetor that the former reaches the position in which it permits the throttle valve of the secondarycarburetor to be opened wide when the latter reaches its wide open position.

In the modification of the invention shown in Figure 3 of the drawing, the primary and secondary carburetors are juxtaposed and made in a single unit which is mounted on the intake manifold M of the engine midway between its ends. In the mixture passage 50 of the primary carburetor there is disposed a butterfly throttle valve which is mounted on a shaft 52 to which is fixed an arm 53 which is connected by a link 61 to'the accelerator pedal of the vehicle and on which is formed a cam 54.

In the mixture passage 55 of the secondary carburetor, there is disposed a butterfly throttle valve 58 which is mounted on a shaft 51. To the shaft 51 there is fixed an arm 58 with a pin 59 on it in the path of the cam 54 on the arm 53 when the latter is moved in the direction to close the throttle valve 5 I. On the shaft 51 there is mounted, so that it may rock, a double-armed lever to with a pin ti on one of its arms in the path of the arm 58 when it is moved in the direction to close the throttle valve 56.

On the secondary carburetor, there is mounted a pressure responsive device which consists of an enclosure 62 with a flexible wall 63 which is connected by a link 64 to the arm of the lever 60 which does not carry the pin GI and is biased by a spring 65 in the direction to close the throttle valve 56. The interior of the enclosure 62 is connected by a tube 66 to the mixture passage 50 of the primary carburetor on the atmospheric side of the throttle valve 5| The cam 54 on the arm 53 on the shaft 52 of the'throttle valve 5! of the primary carburetor is so shaped that it holds the throttle a v 56 which constitute the toggle.

of the secondary carburetor closed until the throttle valve of the primary carburetor has been opened to a pre-selected extent, e. g., about onehalf, and, thereafter, permits the throttle valve of the secondary carburetor to open gradually as the throttle valve of the primary carburetor is opened and to be opened wide when the throttle valve of the primary carburetor reache its wide open position. The connection of the tube 66 to the mixture passage of the primary carburetor on the atmospheric rather than the engine side of the throttle valve 5! obviates a valve like the valve 40 in the embodiment of the invention shown in Figures 1 and 2 in the duct which connects the interior of the enclosure 62 to the mixture passage. The embodiment of the invention shown in Figure 3 operates similarly to the embodiment shown in Figures 1 and 2 and it is thought that its operation will be understood without further explanation.

In the modification of the invention shown in Figures 4 and 5 of the drawing, as in the modification in Figure 3, the primary and secondary carburetors are juxtaposed and made in the same unit which is mounted on the intake manifold I l of the engine midway between its ends.

In the mixture passage 16 of the primary carburetor, there is disposed a butterfly throttle valve H which is mounted on a shaft 12. To the shaft 12 there is fixed a double-armed lever '13 with pins 14 and 15 on its arms which is connected to the accelerator pedal of the vehicle by a link 90. On the lever 1'3 between and in the paths of the pins M and 15, there is mounted so that it may rock on the shaft 12 an arm 16.

In the mixture passage ll of the secondary carburetor, there is disposed a butterfly throttle valve 18 which is mounted on a shaft 79 to which there is fixed a double-armed lever 80. To one 'arm of the lever 80, there is connected a spring 8| which biases the throttle valve toward its closed position. The other arm of the lever 80 is connected by a toggle 82 to the arm 76 which is mounted so that it may rock on the shaft 12 on which the throttle valve of the primary carburetor is mounted. An ear 83 on one of the links which constitute the toggle 82 prevents the toggle moving over center upwardly.

On the secondary carburetor, there is mounted a presssure responsive device which consists of an enclosure 84 with a flexible wall 85 which is connected to the toggle 82 by a rod 36 and a link 81 with a right-angularly disposed end portion which forms the pintle which connects the links A spring 88 biases the diaphragm 85 in the direction to break the toggle 82 downwardly. The interior of the'enclosure 84 is connected by a tube 89 to the mixture passage 10 of the primary carburetor on the atmospheric side of the throttle valve.

When an engine equipped with the embodiment of the invention shown in Figures 4 and 5 is not operating, the parts of the carbureting apparatus occupy the positions in which they are shown in Figure 4. The throttle valve of the primary carburetor is held closed by the usual spring which also, through the intermediaries of the pin 15 and the toggle 82 adds its force to that exerted by the spring 8] to hold the throttle valve of the secondary carburetor closed.

During the initial opening movement of the throttle valve H of the primary carburetor, the suction in the intake manifold I I applied to the diaphragm 85 is insufiicient to counteract the spring 88 and, therefore, as shown in solid lines tions the limits of which are controlled by the operation of the engine, means actuated by the pressure difference between the atmosphere and a passage leading to one of said throttles for determinin the limits to said range of positions under various conditions of operation of said engine, means for holding said secondary throttle in closed position during the operation of said primary throttle in said range of positions, means operable by the movement of said primary throttle beyond said range of positions for opening said secondary throttle, and means for closing said secondary throttle in response to a decrease in pressure in said passage leading to said one of said throttles below the limit required to open said secondary throttle in response to said movement of said primary throttle.

6. A charge forming device comprising primary and secondary carburetors having passages therein for supplying combustible mixtures to the cylinders of an internal combustion engine, primary and secondary throttles in said passages to control the supply of said mixtures to said cylinders, a lever having spaced abutment means thereon and rigidly secured to said primary throttle for opening and closing said primary throttle, an arm movable about the axis of said primary throttle and between said abutment means, a

lever secured to said secondary throttle for opening and closing said secondary throttle, resilient means associated with said secondary throttle and tending to retain said secondary throttle in closed position, means connecting the end of said arm with said secondary throttle lever for opening said secondary throttle in response to engagement between said arm and one of said stops and during the opening movement of said primary throttle, and means associated with said connecting means and operative in response to the flow of fluid in one of said passages leading to said throttles for determining the position at which said abutment engages said arm.

7. A charge forming device comprising primary and secondary carburetors having passages therein for supplying combustible mixtures to the cylinders of an internal combustion engine, primary and secondary throttles in said passages to control the supply of said mixtures in said cylinders, means for opening said primary throttle to a position within a range of positions for said primary throttle, means for holding said secondary throttle in closed position during the operation of said primary throttle in said range of positions, means operable by movement of said primary throttle beyond said range of positions for opening and closing said secondary throttle, and means operable in response to the flow of fluid in one of said passages to said throttles for controlling said last mentioned means.

8. A charge forming device comprising primary and secondary carburetors having passages therein for supplying combustible mixtures to the cylinders of an internal combustion engine, primary and secondary throttles in said passages to control the supply of said mixtures to said cylinders, means for opening said primary throttle to a position within a range of positions for said primary throttle, means for holding said secondary throttle in closed position during the operation of said primary throttle in said range of positions, means operable by movement of said primary throttle beyond said range of positions for opening and closing said secondary throttle, and means responsive to the difference in pressure between the atmosphere and said passage leading to said primary throttle for controlling said opening and closing movements of said secondary throttle by said last mentioned means.

ADOLPI-l' F. BRAUN.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 2,075,330 Angell, Jr., et a1. Mar. 30, 1937 2,193,533 Kishline Mar. 12, 1940 2,269,930 Ericson et al. Jan. 13, 1942 2,313,258 Olson Mar. 9, 1943 2,317,625 Mallory Apr. 27, 1943 2,362,879 Bicknell Nov. 14, 1944 2,376,732 Strebinger May 22, 1945 2,420,925 Wirth May 20, 1947 2,421,800 Martin June 10, 1947 2,430,693 Udale Nov. 11, 1947 2,452,698 Strebinger Nov. 2, 1948 2,460,046 Vincent Jan. 25, 1949. 

